• 한국자동차공학회논문집
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• 제7권8호
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• pp.272-281
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• 1999

Cylindrical panels are widely used as aircraft fuselages and rocket etc, and the cutouts for weight reduction or wiring at such structures tend to cause the stress concentration and the local radial displacement so that seriously effect the stability of structures. In this paper, for the cylindrical composite panel with coutout at the center, the buckling and postbuckling behaviour regarding the shape and size of cutout is analyzed by finite element method. Also the lamination mechanism , changing bending stiffness and fiber orientation angle variation are researched to be regarded in studying the laminated composite materials.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.1064-1081
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• 2014

This paper presents a numerical analysis of slamming and whipping using a fully coupled hydroelastic model. The coupled model uses a 3-D Rankine panel method, a 1-D or 3-D finite element method, and a 2-D Generalized Wagner Model (GWM), which are strongly coupled in time domain. First, the GWM is validated against results of a free drop test of wedges. Second, the fully coupled method is validated against model test results for a 10,000 twenty-foot equivalent unit (TEU) containership. Slamming pressures and whipping responses to regular waves are compared. A spatial distribution of local slamming forces is measured using 14 force sensors in the model test, and it is compared with the integration of the pressure distribution by the computation. Furthermore, the pressure is decomposed into the added mass, impact, and hydrostatic components, in the computational results. The validity and characteristics of the numerical model are discussed.

• 대한기계학회논문집A
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• 제30권12호
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• pp.1603-1610
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• 2006

In this paper compressive characteristics of composite egg-box panels were investigated and energy absorption was calculated from the nominal stress-strain relations obtained by the compressive tests. Several different stacking sequences and number of plies were introduced for investigation of static compression characteristics and the energy absorption rates of composite egg-box panels. The compressive stress-strain relation and energy absorption of various composite egg-box panels were compared with those of aluminium egg-box panels. From the test results it was found that the fracture behavior of composite egg-box panel was affected by stacking angle causing different local deformation, during lay-up and draping processes and types of prepreg; that is, plain weave carbon/epoxy and 4-harness satin glass/epoxy. The energy absorption capacity of composite egg-box panels were proved to be higher than that of aluminium egg-box panels with low mass.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권3호
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• pp.159-173
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• 2011

The two different numerical approaches for solving the nonlinear ship wave problem are discussed in the present paper. One is based on a panel method, which neglects the viscous effects. The other is based on a finite volume method, which take into account the viscous effects by solving RANS equations. Focus is laid upon on the advantages and disadvantages of two methods. The developed methods are applied to calculating the flow around Series 60 hull to validate the performance of the present nonlinear methods. Although the two methods employ quite different numerical approaches, the calculated wave patterns from both methods show good agreements with the experiments. However the potential method simu-lates the global wave pattern accurately, while the viscous method shows better performance for the local wave prediction near a ship.

• Journal of Preventive Medicine and Public Health
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• 제56권1호
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• pp.88-94
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• 2023

Objectives: This study examined how deprivation differed by region and the effect those differences had on suicidal ideation among the local population. Methods: Data collected over 10 years (2012-2021) in the Korea Welfare Panel Study were organized into 3 categories: metropolitan, city, and rural. A panel analysis was conducted on the impact of deprivation indices, socio-demographic characteristics, and life satisfaction on suicidal ideation in each category. Results: Income, divorce status, family relationship satisfaction, and medical deprivation had a significant impact on suicidal ideation in metropolitan areas, whereas these variables did not have significant effects in rural areas. In other words, income, family, and medical support were more impactful in city areas. Conclusions: Although the deprivation index was higher in rural areas than in city areas due to an aging population and reduced income levels, the mental health of rural residents was found to be generally better than that of city residents. The possibility that this is related to the strength of relationships within the respective communities should be considered in light of recent discussions on relational welfare.

• Structural Engineering and Mechanics
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• 제21권4호
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• pp.407-422
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• 2005

Plate elements in fully profiled sandwich panels are generally subjected to local buckling failure modes and this behaviour is treated in design by using the conventional effective width method for plates with a width to thickness (b/t) ratio less than 100. If the plate elements are very slender (b/t > 1000), the panel failure is governed by wrinkling instead of local buckling and the strength is determined by the flexural wrinkling formula. The plate elements in fully profiled sandwich panels do not fail by wrinkling as their b/t ratio is generally in the range of 100 to 600. For this plate slenderness region, it was found that the current effective width formula overestimates the strength of the fully profiled sandwich panels whereas the wrinkling formula underestimates it. Hence a new effective width design equation has been developed for practical plate slenderness values. However, no guidelines exist to identify the plate slenderness (b/t) limits defining the local buckling, wrinkling and the intermediate regions so that appropriate design rules can be used based on plate slenderness ratios. A research study was therefore conducted using experimental and numerical studies to investigate the effect of plate slenderness ratio on the ultimate strength behaviour of foam supported steel plate elements. This paper presents the details of the study and the results.

• 한국철도학회논문집
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• 제11권5호
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• pp.465-470
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• 2008

본 논문에서는 철도 차량용 허니콤 판재를 대상으로 음투과 손실을 검토한다. 허니콤재의 음투과 손실을 예측하는 데에는 등가 직방성 평판 모델과 등가 질량법칙을 적용한다. 음투과 손실의 예측치를 측정치와 비교하여 예측 모델의 신뢰도와 한계를 검토한다. 또한 일치효과와 국부공진 효과가 차음성능에 미치는 효과를 검토한다. 본 연구는 국부공진 주파수대역을 적절히 적용한다면, 등가 직방성 평판 모델을 허니콤재의 음투과손실 예측모델로 사용 할 수 있음을 보인다. 최종적으로, 국부 공진에 의한 차응성능의 급격한 저하에 대한 대책을 제시하고 그 차음 성능에 대한 효과를 분석한다.

• 디지털융복합연구
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• 제12권7호
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• pp.65-76
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• 2014

본 논문은 우리나라의 1인당 지방재정지출이 1985-2011년 기간 동안 수렴하고 있는 지 여부를 광역자치단체 자료를 이용하여 검증하고 있다. Skidmore et al.(2004)의 구조적 모형을 이용하여 1인당 재정지출증가율 방정식을 추정한 결과 우리나라의 1인당 지방재정지출이 수렴하는 것을 확인할 수 있었다[23]. 더욱이 재정지출 증가율에 기여한 것은 노령인구 증가율이라는 것이 확인되었고, 5개 분야로 지방재정지출을 구분하여 수렴여부를 분석한 결과 기능별 재정지출의 유형에 따라 수렴속도가 다른 것으로 나타나 공공투자지출의 수렴속도가 공공소비지출의 수렴속도 보다 빠른 것으로 나타났으며, 경제개발비 지출의 수렴속도가 사회개발비 지출의 수렴속도보다 빠른 것으로 나타났다. 향후 연구에서는 개별 지방공공재의 혼잡도를 고려한 지방공공서비스의 수렴에 대하여 분석하는 것이 중요한 것으로 보인다.

• 대한지리학회지
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• 제48권1호
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• pp.151-165
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• 2013

지방정부로 구성된 국제환경 협의회(ICLEI)는 범지구적 차원에서 기후변화를 완화시키기 위해 만들어진 기구이다. 지방정부들은 ICLEI를 통해 각 정부가 배출하는 온실가스를 정확히 측정하고자 관련 규약을 만들었다. 본 논문은 ICLEI 규약의 한계점을 지적한다. 온실가스배출관련 항목들을 지방정부관점에서 구분하고, 또 국가차원에서 요구하는 항목들과 일치시킨다는 점에서 이 규약은 실용적이라 할 수 있다. 특히 '이중측정'과 '탄소배출할당' 문제를 해결할 수 있는 사회적 기반을 마련한 부분은 지방정부들이 기후변화에 적극적으로 대응하고자 하는 의지로 해석할 수 있다. 하지만, 그 제한점은 다음과 같다. '생체연료연소에 의한 이산화탄소배출'을 온실가스로 취급하지 않는 점과 '간접이중측정'을 간과한 점은 온실가스배출량의 정확한 측정을 저해할 것으로 예상되며, 이들을 수정보완해야 지방정부들이 기후변화를 완화시키는데 있어 실제로 기여할 수 있을 것이다.

• Journal of Preventive Medicine and Public Health
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• 제46권1호
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• pp.1-9
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• 2013

Objectives: We examined the association between social expenditures of the local government and the mortality level in Korea, 2004 to 2010. Methods: We used social expenditure data of 230 local governments during 2004 to 2010 from the Social Expenditure Database prepared by the Korean Institute for Health and Social Affairs. Fixed effect panel data regression analysis was adopted to look for associations between social expenditures and age-standardized mortality and the premature death index. Results: Social expenditures of local governments per capita was not significantly associated with standardized mortality but was associated with the premature death index (decline of 1.0 [for males] and 0.5 [for females] for each expenditure of 100 000 Korean won, i.e., approximately 100 US dollar). As an index of the voluntary effort of local governments, the self-managed project ratio was associated with a decline in the standardized mortality in females (decline of 0.4 for each increase of 1%). The share of health care was not significant. Conclusions: There were associations between social expenditures of the local government and the mortality level in Korea. In particular, social expenditures per capita were significantly associated with a decline in premature death. However, the voluntary efforts of local governments were not significantly related to the decline in premature death.